Talk:Phosgene

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Unlike nerve agents, phosgene must be inhaled to cause harm and cannot be absorbed through the skin.

Doesn't it also have a blinding action on the eyes? Is this the gas that blinded so many WW1 soldiers, or was that something else? -- Chris Q 08:26 Mar 19, 2003 (UTC)

The link to the MSDS sheet does not work I would fix this but I am afraid of making a mistake. ~Chemiker 17:45 Mar 15, 2005

The picture at the top right of the article is of the compound Cl2O... there is no C, while the formula given for phosgene is COCl2, which has a C... Where's the missing C? 66.102.74.252 04:20 May 29, 2005

  • The missing carbon is in the middle, at the intersection of the bonds. It is conventional not to write the C for carbon in organic structures. The external link has now been fixed. Physchim62 09:09, 29 May 2005 (UTC)

Chloroform → Phosgene[edit]

This page, which purports to instruct the creation of chloroform, cautions that stored chloroform can mutate into phosgene. Is this true? What's the reaction? Thanks. Ayeroxor 11:30, Jun 4, 2005 (UTC)

  • This is a known (if minor) hazard of storing chloroform, yes. You can find the information on its International Chemical Safety Card or in the NIOSH Pocket Guide to Chemical Hazards. Commercial chloroform is normally supplied containing 0.5–1.0% ethanol as a stabilizer for this reason: the ethanol reacts with any phosgene formed to produce diethyl carbonate. I'm not sure of the exact details, but it is a free radical reaction initiated by either heat or light (always store chloroform in brown glass bottles). The oxygen atom comes from any oxygen or water present in the medium. The quantities of phosgene formed in laboratory use of chloroform are not usually large enough to pose problems of toxicity, but the reaction can be dangerous either in industrial use or in case of fire. I will add the information to Chloroform when I get a minute! Physchim62 12:38, 4 Jun 2005 (UTC)

i hv tried to produce it @ home by exposing chloroform to moist air in presence of sunlight,but it doesn't work. Anyways, i don't know how to identify wheather PHOSGENE is produced or not!

I removed the leading space from the above anonymous comment to eliminate formatting as a boxed line. Jerry lavoie 20:12, 2 January 2007 (UTC)
Phosgene can be produced in laboratory scale by vigorous oxidation of chloroform. However, any preparation of phosgene is russian roulette, if not done by a chemist in a proper laboratory. Don't try it, it could kill you.--84.163.103.210 (talk) 03:09, 24 February 2008 (UTC)

Production[edit]

Why is there production information on phosgene in the article? Except terrorists, would there be anyone interested in making phosgene?

  • Yes, it is a major industrial chemical: obviously the article at present doesn't make this clear enough! It is usually produced on the same site in which it is used, to avoid transportation problems. Physchim62 18:20, 24 September 2005 (UTC)
  • If a terrorist wants to find this information out, they can easily do that, whether or not Wikipedia has the information. These things are well known and well-published. Ed Sanville 10:46, 22 April 2006 (UTC)
  • Not being one to point out the obvious but the production of phosgene requires chlorine gas, which in itself is a potent chemical weapon. Also, just to hammer home the point made by Edsanville, I'm looking at a Downs Cell (solid sodium and chlorine gas production) right now in a book called Descriptive Inorganic Chemistry (Rayner-Canham and Overton) of which there are several copies in the public library of my university. Although, as an aside, I'm a little fed up with people censoring science because of trrr. I'm reminded of an episode of the Simpsons where the Reverend's Wife goes: "Oh, won't somebody please think of the children?" every time someone brings up the subject.GreatMizuti 14:12, 10 June 2006 (UTC)
    • I don't think that anybody's censored it. If you think that it should be in the article, add it. :) – ClockworkSoul 15:08, 10 June 2006 (UTC)

I don't think this should be in the article. Because it's beyond the scope. Why do we need to know how to make war gas? Too much detail.

173.178.151.144 (talk) 04:19, 12 August 2014 (UTC)

Mechanism of toxicity[edit]

What is the mechanism of toxicity of phosgene gas? Ed Sanville 10:45, 22 April 2006 (UTC)

Phosgene → Chloroform[edit]

These sentences from the article don't make sense:

Upon ultraviolet radiation in the presence of oxygen, chloroform forms significant amounts of phosgene via a radical reaction. Brown glass flasks for chloroform prevent this reaction.

How is this reaction possible? COCl2 + O2 ≠ CHCl3, as there is no hydrogen on the left side of the equation, and ultraviolet radiation is not powerful enough to cause a nuclear reaction. ~ Oni Lukos ct 21:10, 2 October 2006 (UTC)

...I did it again. I misinterpereted a chemical reaction. Granted, this phrasing was rather...poorly phrased, but still. Just pretend as though this section doesn't exist ~ Oni Lukos ct 23:06, 7 October 2006 (UTC)
Consider it ignored :) Incidentally, it's not just the brown glass (although chloroform should not be stored in colorless glass): most commercial chloroform contains about 0.5% ethanol to scavange the phosgene which is formed. Physchim62 (talk) 11:20, 9 October 2006 (UTC)

Colourless green compounds sleep furiously[edit]

The article says: "Phosgene gas has no color but may appear as a white or yellowish haze when released into air." That seems to be a self-contradiction; if phosgene has no colour, how can it be "yellowish"? Is the colour due to an impurity? 216.59.230.140 01:24, 16 December 2006 (UTC)

Just as water has no color, but can appear blue or green under certain viewing or lighting conditions, this is due to selective refraction of light, and not due to any color in the substance itself. Jerry lavoie 20:12, 2 January 2007 (UTC)

I'm not a chemist but I had a discussion recently with someone who sells butane and propane. This question has nothing to do any accident or lawsuit involving phosgene or LP-gases, but I am inquiring on the accuracy of this person's statement:

He says that on his ranch someone accidently used an anhydrous ammonia tank that had not been properly purged as a propane tank and had it filled with an LPG mix of propane and butane. He says that the NH3 molecules on the interior surface picked up the butane or combined with and and when it was burned in a space heater, created phosgene gas (carbon monoxide from burning the hydrocarbon combined with chlorine molecules in the ammonia compound. I said this was not possible unless chlorine was present in the ammonia or ammonium chloride was involved.

Is that possible? I would appreciate any discussion from a reputable source to settle this argument.Jbjoseph 18:36, 31 January 2007 (UTC)

I believe phosgene also occurs as an equilibrium reaction.

CO + Cl2 <---> COCL2

Toxicology[edit]

The deadly and insidious toxicity of phosgene upon inhalation is not mediated by hydrochloric acid formed by hydrolysis. Reasons are:
1. Median lethal concentrations of phosgene in mammals are two decimals below those of HCl that can form. In other words: low and medium concentrations of phosgene in the air do produce lung injury, that could be achieved only by many hundreds of times the overall amouth of HCl, that would be formed by complete hydrolysis of the phosgene inhaled; even taking the high water solubility of HCl gas into account.
2. In acute intoxications, there are normaly no signs of significant acid exposure, such as acidosis.
3. The short characteristic of phosgene as a chemical given is already giving a hint, what mechanisms are involved in its incredible pulmonar toxicity: yes, it's highly electrophile. It acts as an alkylant (or, acylant) agent and readily attacks functional groups such as the thiole gruop, -SH, the amino group, -NH2, or activated hydroxyl group, -OH; it forms intermediary isocyanates, chlorocarbonates and chlorothiocarbonates within the proteins and other essential molecules in the cell membranes of alveoles and tiny capillaries, perfuding them. This is consistent with the effects of other alkylant (acylant) chemicals upon inhalation: much the same type of intoxication is caused by dimethyl sulfate, allyl chloride, benzyl chloride, sulfur mustard or diazomethane if these are inhaled.
4. Unfortunately, my sources are all not in english.
Could someone expert in the field of toxicology be so kind and take an eye upon the subject? Phosgene is, after all, one of the most important industrial chemicals and poses a considerable thread of poisoning, let alone its historical relevance (it were phosgene and diphosgene that killed ~80% of chemical warfare casualties in world war 1). Thanks.--84.163.103.210 (talk) 03:06, 24 February 2008 (UTC)

Excellent suggestions, let me see what I can find. It does seem unlikely that HCl is the root of its toxicity.--Smokefoot (talk) 03:20, 24 February 2008 (UTC)


Irak[edit]

How about someone posting a reference to the discovery of vials of phosgene by Iraq weapons inspectors in the United Nations building on 30 Aug 2007?

Here's the link: [http://today.reuters.com/news/articlenews.aspx?type=topNews&storyid=2007-08-30T170627Z_01_N30440927_RTRUKOC_0_US-UN-CHEMICALS.xml&src=rss&rpc=22&sp=true

-- -- —Preceding unsigned comment added by 128.194.23.43 (talk) 18:05, August 30, 2007 (UTC)

With a boiling point of 8°C or so the Iraky desert seems an ideal place for this stuff.--Stone (talk) 18:55, 1 March 2008 (UTC)
If you ment its potential as a CW agent, that's quite independent from its b.p.; it would be only a question of weaponization (sulfur mustard, with b.p. of 212 - 214°C is equally viable). If you ment the fact that it was found in vials, those are normally sealed massive glass ampoules, so one can store them in wide temperature ranges.--84.163.124.142 (talk) 10:13, 3 March 2008 (UTC)

Phosphine - Phosphene[edit]

Although not related, both these words should be tagged in the article or perhaps above. Phosphine is also a toxic gas and as the words sound similar, it may avoid confusion.Htcs (talk) 02:34, 9 September 2008 (UTC)

Mech of toxicity[edit]

Many intelligent nonchemists are under the impression that phosgene's lethality arises from the release of HCl due to its hydrolysis. But an authoritative text and the chemistry described in the article explain that the mechanism is otherwise. Phosgene preferentially reacts with amino groups, it does not hydrolyze (as you seem to understand). The reaction with amine groups is similar to its basic organic chemistry:

4 RNH2 + COCl2 → (RNH)2CO + 2 RNH3Cl

Ullmann's Encylopedia of Industrial Chemistry is widely recognized, in the first world at least, as an authoritative source of chemical information. Your Professor Aggrawal is not recognized as an authoritative source, although I am sure that he is well intentioned and a nice person. Your misunderstanding is a common one (I used to buy it) but upon reflexion it makes no sense since many other hydrogen chloride sources such thionyl chloride are not nearly as lethal.--Smokefoot (talk) 22:53, 4 April 2010 (UTC)

Mistake in density units[edit]

It looks like the density of the gas at 15°C has the wrong units: it should be (g/L), instead of the reported (g/cm3). (As it currently reads, the gas at 15°C is ~3 times denser than the liquid at 0°C!) Frank Somer (talk) 22:32, 8 November 2010 (UTC)

Carbon tetrachloride[edit]

When I was a lad I lived in a house which had a wartime air-raid shelter in the back garden. On a wall inside there was a round glass bulb (larger than a cricket ball) which was blue or contained blue liquid. I was told this was carbon tetrachloride used as a "fire grenade". Later a college-mate told me that using these could cause the creation of phosgene. Is that true? Unbuttered parsnip (talk) mytime= Thu 12:42, wikitime= 04:42, 6 November 2014 (UTC)

Yes and yes. Tetrachloromethane (carbon tetrachloride) was used as a fire extinguishing agent, prior to ca. 1950 and it could (and did) produce i.a. phosgene if it came into contact with glowing-hot heavy metals (such as iron or copper) in the presence of air. Besides its carcinogenity and intrinsic toxicity, this was one of the major reasons to phase it out post-WW 2. Cheers,--37.49.110.89 (talk) 19:46, 2 March 2015 (UTC)